1. Field of the Invention
This invention relates to improvements in a taker gripper for loom use, which result in more effective weft clamping and hence a considerable reduction in the danger of the weft escaping from the gripper during its transport, even at the high operating speeds required of modern looms, together with easier release of said weft at the end of its travel.
More specifically, the invention relates to improvements in the taker gripper of our preceding British Patent Application GB-A-2 083 844 published Mar. 31, 1982.
2. Description of the Prior Art
In said patent the gripping and clamping members of the taker gripper consist of a wedge axially movable within a hook positioned horizontally at one end of the gripper body, the wedge being maintained elastically pressed within said hook by a spring acting on that end of a lever extending externally to the gripper body, the lever being hinged at its center to said gripper body and having the end of said wedge hinged to its other end, said hook and said wedge being shaped to form between them, on one side, a narrow V recess. In this manner on penetrating into said narrow V recess, the weft is progressively inserted therein until it becomes wedged to hence remain trapped, it being released in known manner by an axial movement of separation of the wedge from the hook, this being achieved automatically by making a fixed cam act on said projecting end of said lever.
Although this known construction involving axial movement between the wedge and hook has the merit of a very small vertical space requirement for the gripper so that the giver grippers used can be very small, resulting in very limited contact between the grippers and the warp yarns, with consequent limited wear of these latter, and the further merit of reliably wedging the weft in its V recess, it is totally unable to protect against weft withdrawal from the top of the taker gripper during the travel of this latter. In this respect, in order to increase the clamping of the weft by the taker gripper and hence reduce the possibility of weft escape during the gripper travel, said wedge of the known taker gripper is provided with a flat spring or helix-twisted flat spring in that part forming said V recess with said hook. However even though this latter construction provides more effective protection against weft withdrawal, it has drawbacks due substantially to the fact that at each axial movement of the wedge, said spring hits against the hook inner wall forming said V recess, leading to wear of the spring and the inevitable formation thereon of small burrs which can compromise the integrity of the weft and damage it irreparably. Again, the small axial movement of separation of the wedge from the hook which occurs automatically each time the taker gripper reaches its end of travel position combined with the fact that the V recess formed by them is necessarily very narrow means that a very small free space is created, this certainly not facilitating the release of the weft from the gripper when in its end of travel position.